NF-75 Long Seam Milling Machine for Cylinders 3-15m Diameter | Kasry, Dezhou, China

The NF-75 is designed for milling grooves along the external welds of cylindrical and conical shells, working at the 4 o'clock position of the workpiece. It runs automatically on workpieces from 3,000mm to 15,000mm in diameter and from 2,000mm to 4,000mm in length, which covers very large structures such as wind power monopiles, pressure vessels, and large chemical containers.

The machine has a 75kW servo spindle motor delivering more than 9,600Nm of torque at 0 to 70rpm, continuously adjustable. It carries a 950mm diameter milling cutter that cuts to a depth of 120mm, or 150mm as an option. A laser distance measuring device controls milling depth so it stays uniform, and Kasry states an accuracy of within ±2mm, which depends on the movement of the barrel (the rotating shell).

The milling cutter disc is designed to match the weld profile, and different groove angles can be customised. The standard configuration is a cutter disc for milling U-shaped grooves. The machine weighs about 12 tonnes and can be moved on site with a crane or forklift.

Why Choose a Long Seam Milling Machine?

Heavy-wall cylinders need accurate weld grooves so the weld can be made with the right geometry. Preparing grooves by gouging or grinding is slow and inconsistent on very thick plate, and depth control is difficult by hand.

• Deep cuts. Up to 120mm deep as standard, and up to 150mm as an option.
• Uniform depth. Laser distance measuring keeps the groove depth consistent.
• Shaped to your weld. The cutter disc is made to the weld profile, with custom groove angles available.
• Very large workpieces. Shells from 3 to 15m in diameter.
• Easy to position. Weighing about 12 tonnes, it can be lifted and moved on site with a crane or forklift.

Machine Specifications

• Model: NF-75
• Workpiece diameter: 3,000mm to 15,000mm
• Workpiece length: 2,000mm to 4,000mm
• Milling cutter: φ950mm
• Cutting depth: 120mm (150mm optional)
• Spindle drive: 75kW servo spindle motor
• Output torque: more than 9,600Nm
• Spindle speed: 0 to 70rpm (continuously adjustable)
• Milling accuracy: within ±2mm, depending on the movement of the barrel
• Depth control: laser distance measuring device
• Voltage and power: AC 380V, 50Hz, 85kW
• On-site movement: crane or forklift
• Dimensions: approx. 4.6 × 2 × 2m
• Weight: approx. 12 tonnes

Condition Available: New

Key Features

• Automatic groove milling of external longitudinal welds
• 75kW servo spindle with more than 9,600Nm torque
• 950mm cutter with 120mm depth (150mm optional)
• Laser distance measuring for uniform depth
• Cutter disc shaped to the weld profile, with custom groove angles
• Handles shells from 3 to 15m in diameter
• Can be moved on site by crane or forklift

Applications

• Weld groove milling on wind power monopiles
• Chemical vessels and containers
• High-pressure and ultra-high-pressure vessels
• Large cylindrical and conical shells in heavy fabrication

Who This Machine Is For

• Wind monopile and offshore wind structure fabricators
• Pressure vessel and heavy chemical equipment manufacturers
• Heavy fabricators preparing thick-wall welds on large shells

Frequently Asked Questions

What does this machine do?
It mills grooves along the external welds of large cylindrical and conical pipes, preparing them for further welding.

What sizes can it handle?
Workpieces from 3,000mm to 15,000mm in diameter and from 2,000mm to 4,000mm in length.

How deep can it cut?
120mm as standard, and 150mm as an option.

How is the depth controlled?
By a laser distance measuring device, which keeps the milling depth uniform.

Can it cut different groove shapes?
Yes. The cutter disc is designed for the weld profile, and different groove angles can be customised. The standard cutter mills U-shaped grooves.

How accurate is it?
Within ±2mm, depending on the movement of the barrel.

How is it moved?
It weighs about 12 tonnes and can be moved on site with a crane or forklift.

Is financing or staged payment available?
Yes. A deposit secures your order and begins production, with the remaining balance due only once your machine has been built, inspected, and is ready to ship.

Should I buy new or used?
This machine is available new, built to order.